Glossary

Afterload- The resistance created by the volume of blood in the vascular system, against which the left ventricle must eject blood during contraction.

Akinetic – Meaning, literally, “without movement,” this term describes the inability to move a part of the body

Aldosterone – A mineralocorticoid steroid produced by the adrenal cortex that enhances sodium and water reabsorption and increases the excretion of potassium in the urine.

Algorithm- A systematic protocol that provides a solution to a problem

Anastomosis – a communication between two vessels; a surgical or pathological formation of a passage between any two normally distinct spaces or organs

Aneurysm – saclike swelling in wall of a vessel

Angina Pectoris – chest pain usually due to interference with the supply of (O2) blood to the heart muscle, usually brought on by excitement of effort

Angiocardiography – injection of radiopaque solution in the vascular system for x-ray examination of the coronary arteries

Aortic Valve – The heart valve that connects the left ventricle with the aorta. It is made of three cusps that close during diastole, preventing the flow of blood back into the left ventricle, and three sinuses that open during systole, allowing the flow of oxygenated blood into the aorta and into circulation.

Arrhythmia – A deviation from the normal rhythmic pattern of the heartbeat.

Arrythmogenic- Capable of inducing an irregular heartbeat.

Arteriole- The smallest of the arteries, the arterioles carry blood to the capillaries and help to regulate vascular resistance and blood pressure.

Asynergy – lack of coordination among parts normally acting in unison

Asymptomatic – Without symptoms

Atelectasis- An abnormal condition characterized by alveolar collapse, which prevents the respiratory exchange of carbon dioxide and oxygen. The condition may be caused by an obstruction in the major airways and bronchioles, by fluid or air in the pleural space causing compression of the lungs, or by a tumor outside the lung.

Atherogenesis – The buildup of plaque in the innermost layers of the lining of the arteries.

Atherosclerosis – one of the most common causes of arterial occlusion, this describes a buildup of localized accumulations of lipid-containing material within or beneath the intimal (inner) surfaces of blood vessels

Atrioventricular (AV) Bundle – Also known as the bundle of His, this band of less-contractile cardiac muscle fibers arises from the distal area of the atrioventricular node, extends across the AV groove to the top of the intraventricular septum, and divides into bundle branches.

Atrioventricular (AV) Node – Located in the septal wall between the left and right atria, the atrioventricular node receives the cardiac impulse from the sinoatrial node and conducts it to the AV bundle, the Purkinje fibers, and the walls of the ventricles.

Atrioventricular (AV) Septum – A small area of membrane in the heart, separating the atria from the ventricles.

Atrioventricular (AV) Valve – A heart valve between the atria and ventricles. The mitral (bicuspid) valve connects the left atrium to the left ventricle. The tricuspid valve connects the right atrium to the right ventricle.

Atrium – There are two atria, both of which empty blood into the ventricles during diastole. The right atrium is supplied with deoxygenated blood from the superior vena cava, the inferior vena cava, and the coronary sinus. The left atrium is supplied with oxygenated blood from the pulmonary veins.

Auscultation – Usually performed with a stethescope, the act of listening to sounds in the carotid arteries and in the body, most often cardiac murmur, bruit, and rales.

Automaticity – The property of specialized excitable tissue, such as the pacemaker cells of the heart, that creates the potential for self-activation.

Autonomic Nervous System – Responsible for the regulation of involuntary functions such as the movement of the cardiac muscle, smooth muscles, and glands, the autonomic nervous system has two divisions: the sympathetic nervous system accelerates the heart rate, raises blood pressure, and constricts the blood vessels; and the parasympathetic nervous system slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles.

Axillary – Relating to the axilla, a small, pyramidal space under the arm (i.e., armpit).

Baroreceptor – Baroreceptors are pressure-sensitive nerve endings in the walls of the atria, the aortic arch, and the carotid sinuses that stimulate central reflexes to adjust and adapt to changes in blood pressure by changing the heart rate, vasodilation, and constriction.

Bayes’ Theorem– A mathematical prediction of the probability of the presence of disease. A positive result, which is a statement of the relationship of test sensitivity and specificity, is interpreted by the clinician as a demonstration of the probable presence of a disease.

Beta-Adrenergic Blocking Agents – Drugs that block the beta-adrenergic receptor, thereby causing decreased rate and force of heart muscle contractions. They are often administered to treat hypertension, angina, and arrhythmias.

Bifurcate – to divide into two branches

Bipolar Lead – Part of an electrocardiogram exam, a conductor with two electrodes that are placed on different regions of the body

Blood volume- equal to the sum of the blood cell and plasma volumes in the vascular system at any time. Cardiac output depends on the amount of blood discharged from the ventricles with each heart beat, stroke volume, and the rate of heart beat

Bradycardia – A condition in which the ventricles beat at a rate of less than 60 beats per minute. Sinus bradycardia, common in athletes, is considered benign. More serious forms of bradycardia include sinus arrhythmia and second- or third-degree atrioventricular block.

Bronchospasm – A contraction of the smooth muscle in the walls of the bronchi that causes a narrowing and obstruction of the respiratory airway. It is usually indicated by a cough with generalized wheezing.

Bundle Branch – The left and right bundle branches are continuations of the atrioventricular bundle, extending from the top of the intraventricular septum. The bundle branches continue the transmission of electrical impulses within the ventricles, passing down the septum and under the endocardium. The bundle branches further subdivide within the ventricles and end in the Purkinje fibers.

Bundle Branch Block (BBB)- a defect in the heart’s electrical conduction system wherein there is a failure of conduction down one of the main branches of the bundle of His, resulting in a widened, abnormal QRS complex. Commonly associated with acute anterior wall myocardial infarction, BBB may be caused by necrosis, ischemia, trauma, or compression of the bundle branches by a tumor. A pacemaker may be inserted to compensate for further anticipated deterioration.

CAD (Coronary Artery Disease )–narrowing of the coronary arteries sufficiently to provide insufficient blood supply to the myocardium. The narrowing, which is usually a result of atherosclerosis, may progress to the point where the heart muscle is damaged due to lack of blood supply

Capillary – One of the microscopic blood vessels that connect the arterioles to the venules.

Capillary Bed – A network of capillaries.

Cardiac Catheterization- A diagnostic procedure in which a catheter is threaded through the circulatory system to the heart. The catheter is usually introduced through an incision in a large vein and/or artery in an arm or a leg.

Cardiac cycle – complete heartbeat consisting of a contraction (systole) and a relaxation (diastole) of both atria and ventricles

Cardiac Output – the amount of blood that is pumped per minute by a ventricle and is the product of rate of beat (stroke rate) and milliliters of blood ejected per beat (stroke volume) according to the following equation:

Cardiomyopathy – a general diagnostic term designating primary myocardial disease

Cardiovascular – pertaining to the heart and blood vessels

Cardiovascular Disease (CVD)- Any of several conditions that affect the functions of the heart and blood vessels, including rheumatic heart disease, atherosclerosis, cardiomyopathy, congestive heart failure, hypertension, and syphilitic heart disease.

Central Nervous System (CNS)- The network, consisting of the brain and spinal cord, that coordinates and controls the entire body. The central nervous system sends information to and receives it from the peripheral nervous system.

Cervical – Relating to the neck or area of the neck.

Chordae tendineae- tendinous cords connecting the two atrioventricular valves to the appropriate papillary muscles in the heart ventricles)

Chronotropic – Affecting the rate of rhythmic movements such as the heartbeat.

Circumflex – curved, like a bow; winding around

Clinical Pathway – A course of treatment likely to result in a favorable outcome and minimized costs, usually based on clinical research, common practice, and consultation of literature.

Congestive Heart Failure A condition that impairs the normal pumping of the heart, caused by myocardial infarction, atherosclerosis, or cardiomyopathy. In CHF, blood is not efficiently ejected from the left ventricle, resulting in volume overload, chamber dilation, and abnormal intracardiac pressure, followed by pulmonary and venous congestion and peripheral edema.

Coronary Artery Bypass Graft (CABG): A surgical procedure that creates new routes around narrowed or blocked coronary arteries. To improve the supply of blood to the heart and relieve pain, a prosthesis or a portion of a blood vessel is grafted onto a coronary artery.

Coronary Artery Disease (CAD) – A condition that affects the coronary arteries, resulting in impaired flow of oxygen and nutrients to the heart.

Coronary sinus – the vessel cavity or passage which receives the cardiac veins from the heart- it opens into the right atrium

Coronary Syndrome – A wide spectrum of signs and symptoms categorized according to severity. The severity determines the extent of coronary artery disease in patients with known or suspected disease.

Defibrillator- A device used to deliver an electric shock to restore a normal cardiac rhythm and rate. A preset voltage is delivered to the myocardium through the chest wall.

Diastole– rhythmic cycle of relaxation and dilation of the heart during which the chambersfill with blood

Ductus arteriosus – a channel of communication between the main pulmonary artery and the aorta of the fetus

Dyskinesis – impaired movement; paradoxical movement

Ejection fraction – ventricles do not completely empty their blood during contraction. This stroke volume represents a fraction of the total volume reached at end-systole. The EF equals the

(EDV – ESV ) divided by EDV

End Artery- Also called a terminal artery, this “dead end” does not connect to another blood vessel.

End-diastolic volume – largest volume attained by the ventricle during a cardiac cycle, depicting the capacity of the ventricle following completion of its filling with blood (at the end of diastolic cycle).

This EDV is the SV

EF .

End-systolic volume – smallest volume attained by the ventricle during a cardiac cycle. ES volume depicts the residual capacity of the ventricle at the end of the systolic cycle. The ESV= EDV – SV

Heart Block – A delay in, or interference with, the transmittal of the cardiac impulse, which can occur in the sinoatrial node, atria, atrioventricular node, atrioventricular bundle, fascicles, or any combination of these areas. Heart block is defined by location and type; for example, a first-degree atrioventricular block describes a delay in the cardiac impulse that is conducted to the ventricles.

Hyperlipemia – an excess of lipids in the blood

Hypertrophy- increase in organ size or bulk as result of functional activity (Usually dysfunction or disease)

Hypokinesis- markedly diminished motion

Hyponatremia– salt depletion

Idiopathic Hypertrophic Subaortic Stenosis (IHSS)-

congenital heart disease that results in abnormal thickening of the ventricular septum and left ventricular wall. Enlargement of the ventricular septum can result in ventricular outflow obstruction.

Infarct – a localized area of ischemic necrosis produced by occlusion of the arterial supply or the venous drainage of the part

Interventricular Septum – A partition separating the ventricles of the heart.

Interstitial – situated between parts or in the interspaces of a tissue

Ischemia – deficiency of blood in a part, due to functional constriction or actual obstruction of a blood vessel

Isoenzyme – A chemical variation of an enzyme that catalyzes the same physiologic reaction.

J Point– The junction of the QRS complex and the ST-segment of the electrocardiogram; also called the junction point.

Lactate Dehydrogenase (LDH)- An enzyme that catalyzes the oxidation of L-lactate to pyruvate. LDH is one of several serum indicators of myocardial infarction.

Left Anterior Descending Artery (LAD )- One of two main branches that descend from the left coronary artery, supplying blood to the anterior wall of the heart.

Left Circumflex Artery (LCx – One of two main branches that descend from the left coronary artery, supplying blood to the left lateral and posterior aspects of the heart.

Left Coronary Artery (LCA )- One of two branches from the aorta, starting in the left posterior aortic sinus, dividing into the left interventricular artery and the circumflex branch. The LCA supplies the ventricles and the left atrium.

Ligamentum arteriosum – (remnant of shunt for fetal blood supply) a fibrous cord extending from pulmonary artery to arch of aorta, the remains of the fetal ductus arteriosus

Lumen – the central cavity in any blood vessel

Mediastinum – the mass of tissues and organs separating the sternum in front and the vertebral column behind

Myocardial Infarction – Necrosis of a portion of cardiac muscle caused by obstruction in a coronary artery due to atherosclerosis, a thrombus, or vasospasm; a heart attack.

Myocardial Perfusion – Blood flow to the heart muscle. Myocardial perfusion is measured using diagnostic imaging, in which a radiotracer

Myocarditis – inflammation of the myocardiumis injected into the bloodstream to reveal areas of insufficient blood flow to the myocardium.

Pericardium – double membranous fibroserous sac enclosing the heart and the origins of the great blood vessels; composed of an inner serous layer (visceral pericardium or epicardium) and an outer fibrous layer (parietal pericardium)

Peripheral Edema- abnormal accumulation of fluid in the intercellular spaces of the extremities

Phosphorylation- the introduction of the trivalent PO group into a molecule

Preload- The degree of stretch of myocardial fibers at the end of diastole.

Predictive Value- The conditional probability that a clinical test result correctly identifies a patient as having or not having a disease. That is, the predictive value of a positive test is the probability that a person with a positive test is a true positive (i.e., does have the disease), and the predictive value of a negative test is the probability that a person with a negative test does not have the disease.

Prognosis – A prediction of the outcome of a disease. A probable outcome is predicted based on the patient’s condition and the course of the disease that has been observed in similar situations.

Pseudoaneurysm – A dilated artery with damage to one or more layers, caused by trauma or the rupture of a true aneurysm.

Pulmonary transit time – time elapsed between visualization of the pulmonary artery and the left atrium and ventricle

Pulse- The regular expansion and contraction of the arteries, corresponding to each beat of the heart as oxygenated blood is ejected from the left ventricle. The pulse can be detected easily on the radial and carotid arteries

Regurgitation- backflow of blood in the wrong direction through a valve

Renin– An enzyme produced and stored in the kidneys that, when released into the bloodstream, affects blood pressure by catalyzing the conversion of angiotensinogen to angiotensin I.

Revascularization – The restoration of blood flow to an organ or a tissue, typically through surgery.

Reverse Redistribution (TL)- an abnormal pattern in which there is uniform distribution on the stress image and the presence of relative defects on the delayed (rest) image. The physiological mechanism for this phenomenon is unknown. Reverse redistribution has been associated with a significant stenosis, the presence of collateral circulation or imaging immediately after a myocardial infarction.

Right Coronary Artery (RCA)- One of two branches from the aorta, the RCA originates in the right posterior aortic sinus, passes along the right side of the coronary sulcus, then divides into the right interventricular artery and a large marginal branch. The RCA supplies the ventricles, the right atrium, and the sinoatrial node.

Risk Factor – A factor that causes a person or a group of people to be particularly susceptible to an unwanted, unpleasant, or unhealthful event. An example is cigarette smoking, which increases the risk of developing a respiratory or cardiovascular disease.

Risk Stratification – The process of identifying patients who are at low, mild-to-moderate, or high likelihood of disease and the possibility of having a future cardiac event. Risk stratification provides critical information to the physician for determining what course of action should be taken both diagnostically and therapeutically.

Rub- Also known as pericardial friction rub. A sound heard through auscultation that occurs when the inflamed pericardial surfaces move against one another. Often a result of pericarditis.

Saphenous – Relating to certain structures in the leg, for example, arteries, veins, or nerves.

Sensitivity – number of positive studies divided by patients with proven disease

Serous – producing a watery secretion

Specificity – number of true negative studies divided by the number of patients without disease

Stroke Volume– the amount of blood discharged from the ventricle with each beat (ED-ES)

Sulcus- shallow groove, depression or furrow on the surface of an organ

Coronary sulcus- the groove on the surface of the heart marking the junction of the atria and the ventricles, completely encircling the heart

Supraclavicular – Relating to the area above the clavicle, or collarbone.

Syncope- Temporary loss of consciousness caused by lack of oxygen to the brain.

Systole- rhythmic cycle of contraction of the heart during which time blood is expelled from the heart’s chambers

Tardokinesis – wall motion is present, but delayed

Thrombolysis – dissolution of a clot

Thrombolytic Therapy – An attempt to dissolve an arterial clot using a thrombolytic agent such as tissue plasminogen activator, urokinase, or streptokinase.

Transducer- A hand-held device that changes electrical impulses into sound waves, then receives the sound wave and converts it back into electrical energy.

Transmural – through the layers or across the wall of an organ or body cavity

Triage– the sorting out and classification of casualties of war or other disaster, to determine priority of need and proper place of treatment.

Troponin– a very sensitive and specific indicator of damage to the heart muscle.

Unipolar Lead – A conductor in the electrocardiograph in which the exploratory electrode is placed on a limb or on the precordium, and the indifferent electrode remains in the central terminal.

Unstable Angina – Severe chest pain with sudden onset, sudden worsening, and recurrence over a period of days or weeks. Unstable angina is a symptom of the onset of acute myocardial infarction and carries a worse short-term prognosis than stable chronic angina.

Vasoconstrictor – a drug that narrows the blood vessels

Vasodilator – a drug that opens the blood vessels

Ventricular Aneurysm – A protrusion, dilation, or lesion in the wall of a ventricle, usually caused by a buildup of scar tissue after the inflammation associated with myocardial infarction. Typically bulging outward during ventricular contraction, the aneurysm is often revealed when recurrent ventricular arrhythmia does not respond to conventional treatment.

Ventricular Fibrillation – A severe form of cardiac arrhythmia characterized by the absence of any organized electric activity or ventricular contraction. Symptoms include a blood pressure of zero, and unconsciousness. CPR, defibrillation, and resuscitative medication must be administered, as death may occur within 4 minutes.

Ventricular Tachycardia- An abnormally high rate of contraction (more than 100 beats per minute) in at least three consecutive ventricular complexes, usually starting distally to the branch bundles.

Venule – the smallest veins that are formed by the union of many capillaries